Geometry Group should track geometryNode rather than handle

- This allows for correct instancing/reuse of OSPRay geometry mesh data
  object within two separate geometry nodes.

- Renamed BIT_node_info extension "instanceID" to "instanceUUID" as it
  is a string value and not true instanceID uint32_t

Author: Bruce Cherniak

sg/importer/glTF.cpp

@@ -302,7 +302,7 @@ void GLTFData::loadNodeInfo(const int nid, NodePtr sgNode)
       auto &nodeId = node.Get("id").Get<std::string>();
       if (!isValidUUIDv4(nodeId))
         std::cerr << nodeId << " is not a valid version 4 UUID\n";
-      sgNode->createChild("instanceId", "string", nodeId);
+      sgNode->createChild("instanceUUID", "string", nodeId);
     }
   }
 

sg/visitors/PrintNodes.h

@@ -38,7 +38,9 @@ namespace ospray {
   inline bool PrintNodes::operator()(Node &node, TraversalContext &ctx)
   {
     std::cout << std::string(2 * ctx.level, ' ') << node.name() << " : "
-              << node.subType() << " : " << NodeTypeToString[node.type()];
+              << node.subType() << " : " << NodeTypeToString[node.type()]
+              << " : " << std::hex << &node;
+
 
     // A couple of usings to make subType strings match types
     using string = std::string;

sg/visitors/RenderScene.h

@@ -275,7 +275,7 @@ namespace ospray {
   inline void RenderScene::createGeometry(Node &node)
   {
     auto geomNode = node.nodeAs<Geometry>();
-    void* geomHandle = reinterpret_cast<void *>(node.valueAs<cpp::Geometry>().handle());
+    void *geomHandle = geomNode.get();
 
     if (groups.find(geomHandle) != groups.end())
       return;
@@ -365,7 +365,7 @@ namespace ospray {
       }
     }
     // update handle
-    geomHandle = reinterpret_cast<void *>(node.valueAs<cpp::Geometry>().handle());
+    geomHandle = geomNode.get();
     if (geomNode->group)
       groups.emplace(std::make_pair(geomHandle, *geomNode->group));
 
@@ -461,7 +461,7 @@ namespace ospray {
 #endif
 
       for (auto &geom : geomChildren) {
-        auto geomHandle = geom->valueAs<cpp::Geometry>().handle();
+        auto geomHandle = geom.get();
         if (groups.find(geomHandle) != groups.end()) {
           auto &group = groups[geomHandle];
           setInstance(group);